Proto-language

A proto-language (alternatively known as a parent language, or common ancestor) in the tree model of historical linguistics is a hypothetical, or reconstructed, typically extinct language from which a number of attested, or documented, known languages are believed to have descended by evolution, or slow modification of the proto-language into languages that form a language family. Occasionally, the German term Ursprache (from Ur- "primordial" and Sprache "language", ) is used instead.